1. Field of the Invention
The present invention relates to concrete materials, and particularly to a synthetic recycled plastic aggregate for use in concrete.
2. Description of the Related Art
Concrete is one of the most important and frequently used materials in civil engineering, such as in high-low buildings, bridges, infrastructure and environmental protection facilities. Concrete is a composition of an aggregate and a binder substance. The binder substance and the aggregate are combined by a moistening agent to allow the binder substance to link with aggregate particles and form a solid block. Generally the aggregate or aggregates make up about 60% to 75% of the total concrete volume. Therefore, the type and proportion of the aggregate used in concrete can significantly impact the weight, strength, durability, and elastic properties, of the concrete. However, as a result of environmental concerns, there has been a growing trend for the use of secondary, industrial, granular and recycled plastic wastes as recycled and/or artificial aggregate instead of natural aggregate in the production of concrete as a direct replacement of coarse/fine natural aggregate. For example, air-cooled, blast furnace, and steel furnace slag have been used to replace coarse aggregate materials and fly ash and furnace bottom ash have been used to replace fine aggregate materials. Furthermore, by product materials, such as silica fume and rice husk ash have been used as supplementary cementing materials as a partial replacement of cement.
Over the last 30 years, worldwide production of plastic grew by more than 500%. Current annual global production is estimated at over 100 million tons and is expected to increase by 3% a year. In the U.K., 7% of plastics are recycled each year, which is a small quantity when compared to the 275 million tons of natural aggregate used in concrete applications. About 80% of the plastic wastes are either left in stockpiles, as landfill material, or is illegally dumped. Most importantly, much of the non-decaying wastes will remain in the environment for hundreds, perhaps thousands of years. The non decaying waste will not only cause a waste disposal crisis, but also contribute to significant environmental problems.
Use of synthetic aggregate in concrete has been limited; however, because synthetic aggregates do not provide the same physical, chemical, or mechanical properties as natural aggregates.
Thus, a synthetic aggregate solving the aforementioned problems is desired.